1. Field of the Invention
The present invention relates to rollers and, more particularly, to rollers for belt filter presses.
2. Brief Description of the Prior Art
Rollers are used in a variety of applications. For example, U.S. Pat. No. 4,399,169 to McGowan discloses a roller for use in paper drying machines having insulated end caps. U.S. Pat. No. 1,872,062 to Burke and U.S. Pat. No. 2,156,395 to Klouman each disclose rollers used in heat treating furnaces.
In the belt press roller art, the most prevalent type of roller used is shown in FIG. 1. The roller A typically has a cylindrical hollow body B made from steel. A pair of end pieces C are welded at each opposing end of the body B to an interior surface D of the body B. A cylindrical shaft E is welded to the end piece C parallel to the interior surface D of the body B and perpendicular to each end piece C.
The belt press roller design shown in FIG. 1 is not without its deficiencies, however. First, the roller A requires four end pieces C, two at each opposing end of the roller body B, due to the stresses placed on the roller A during operation. This results in higher material and manufacturing costs. Second, because internal, non-linear welds F, G are needed to attach the various parts together, there is a demonstrated increased probability that the welds F attaching the end pieces C to the interior surface D of the body B and the welds G attaching the shaft E to the end pieces C will fail during operation of the roller A. The most common problem is a failure of the welds G connecting the end pieces C to the shafts E because the welds G adjacent the shafts E are subjected to higher stresses than the welds F positioned adjacent the end pieces C and the interior surface D of the roller body B.
To obviate the problems associated with the prior art rollers, the present invention generally includes a roller body having two opposing ends, with an end piece connected to each opposing end of the roller body. Each end piece has a first side, a second side, a center portion, and a rim, wherein the second side of each end piece forms a thickened portion that preferably tapers or otherwise becomes thinner in a direction away from the center portion of each end piece toward the rim of each end piece. The rim can be extended toward the roller body, allowing different shapes.
The roller body preferably forms an internal hollow cavity, is cylindrical in shape, and may extend about a longitudinal axis. A first shaft is positioned perpendicularly adjacent to the center portion of the first side of one of the two opposing solid end pieces, and a second shaft is positioned perpendicularly adjacent to the first side of the other one of the two opposing solid end pieces. The first shaft and the second shaft each extend about the longitudinal axis of the roller body, and are preferably formed integrally with the first side of each end piece.
The thickened portion on the second side of each end piece extends into the hollow cavity and is symmetric about the longitudinal axis of the roller body, but the thickened portion does not contact the cylindrical roller body, and the thickened protrusions are not connected to each other. The thickened portion can form a number of different shapes (seen when an end piece is cut by an imaginary plane passing through the center portion of the end piece, perpendicular to the second side of the end piece). The thickened portion provides more material in the area of highest stress while dissipating toward the rim of the end piece, which is the area of lower stress.
It is therefore an object of the present invention to provide a roller that is less expensive to manufacture and eliminates welds near the area of the roller subjected to the greatest amount of stress.